1. Field of the Invention
The present application is directed to a shelving system in which several cooperating components are formed with two sets of locking tapers, and particularly to a shelving system in which frusto-conical shapes are provided to upper and lower legs, and to a shelf in order to provide a simple, effective interlocking design.
Shelving systems are widely known and commonly used in both the business, commercial, and residential environments. Traits of commercially successful shelving systems include economical manufacture, efficient packaging, easy assembly, and stability in use. However, many of the known shelving systems fall short of meeting all of the requirements described above. For example, U.S. Pat. 543,422 (Ernest) describes a system adapted for use as a folding voting booth. FIG. 2 shows a table body having four metal angle braces, one at each corner. As seen in FIG. 6, each angle brace has a frusto-conical hole therein. In addition, a roof covers a portion of the top of the hole to provide a smaller opening. The frusto-conical end of a lower wooden leg is inserted into the bottom of the hole in each brace. Then, the end of an upper wooden leg is inserted into the opening in the roof of the hole and then into a bore in the frusto-conical end of the lower leg, as depicted in FIG. 4. When weight is placed on the table, the brace will be pressed downward onto the lower support leg, thereby tightening the grip of the brace on the lower leg. However, this will not readily tighten the grip of the lower leg on the upper leg.
U.S. Pat. No. 1,512,867 (Sutter) discloses a pie rack in which frusto-conical hollow legs are stacked upon each other in telescoping fashion, as depicted in FIG. 3. Openings are provided in the side walls of each leg for receiving lugs formed on a shelf. This apparatus is difficult to assemble and places great stress on the shelf lugs. Therefore, the lugs must be reinforced, and assembly time can be lengthy.
U.S. Pat. No. 3,220,773 (Burns) discloses a multiple use knockdown unit in which frusto-conical legs pass through round holes in a horizontal shelf, as shown in FIG. 5. However, no provision is made for stacking multiple units, and imprecise tolerances on either the legs or the shelf holes will result in an unstable shelving system.
U.S. Pat. No. 3,873,511 (Maslow), which is assigned to the assignee of the subject invention, discloses a shelving system having a removable corner structure. As shown in FIG. 6, the corner structure 24 is coupled to a horizontal shelf 12 and adapted for coupling to the support post 50. A sleeve 60 is positioned on the support post 50 by an annular rib and groove structure 66. The sleeve 60 has an external frusto-conically shaped tapered surface adapted to mate with the tapered internal surface of the corner structure 24. Thus, a tight and secure fit is obtained between the sleeve 60 and the corner structure 24.
U.S. Pat. No. 3,424,111 (Maslow), also assigned to the assignee of the subject invention, discloses a shelving system that uses an annular rib and groove structure to position a sleeve on a vertical post thereby to mount a horizontal shelf. As shown in FIG. 2, a post 34 includes a plurality of horizontal grooves 36 which are adapted to mate with a corresponding rib on mating frusto-conical sleeve members 40 and 42. The members 40 and 42 are secured to the post 34. The sleeve members 40 and 42 have a frusto-conical outer surface which is adapted to support the horizontal shelf 10 through a similar frusto-conical surface therein.
U.S. Pat. No. 4,138,953 (Tashman) discloses an adjustable shelf assembly in which a shelf 11 has a hole in each corner thereof. As shown in FIGS. 4 and 5, a leg 12 is inserted in the hole until a groove 13 on the leg is disposed therein. Then, a collar 39 is inserted into the hole, from the bottom, about the leg until a tongue 42 on the collar mates with the groove 13. The collar 39 has a frusto conical outer surface adapted to engage a frusto-conical inner surface of the shelf hole. The difficulty of assembly of this system can be readily appreciated since forcing the collar 39 into the shelf hole may be difficult and require precise tolerances.
U.S. Pat. No. 3,664,274 (Bustos) discloses an adjustable merchandise support with molded shelves. Shelf 12 includes a plurality of corner holes 16, each having tapered surfaces 20. Each leg 26 is provided with a corresponding tapered wedge 22 which is adapted to engage the tapered surface 20 within each corner hole 16. Weight placed upon the shelf will tend to tighten the connection between the horizontal shelf 12 and the legs 26. However, when adding additional legs and additional shelving, no provision is made for tightening the grip of an upper leg onto a lower leg. In addition, the many requisite parts of this shelving apparatus make it expensive to manufacture and difficult to assemble.
Therefore, the known shelving devices such as those mentioned above share one or more of the disadvantages at least in certain applications.
U.S. Pat. No. 557,174 (Turner) discloses a rail bond connection mechanism utilized in a wholly unrelated field. As shown in FIG. 6, a first conductor A has a frusto-conical outer surface adapted to fit within a complementary frusto-conical inner surface of a sleeve C. Sleeve C also has a frusto-conical outer surface which is tapered in a direction and sense opposite than is its frusto-conical inner taper and adapted to mate with a frusto-conical inner surface of hole in a rail D. Thus, as force is applied on conductor A, it tightens the connection between conductor A and sleeve C, and at the same time, causes the connection between sleeve C and rail D to be tightened in turn.